Concrete structures

ABSTRACT

In a structure comprising a precast concrete sections, the sections are arranged in generally edgewise relationship and the edge portions of adjacent sections are spaced apart and have relatively flexible or resilient material (such as bituminous or elastomeric material) applied thereto; a mass of setting composition is provided between the edge portions of each two adjacent sections, to form joints between said sections, and the structure is stressed by means of stressing rods or cables so as to maintain said joints in permanent compression and to render them substantially fluidtight.

I United States Patent 1151 3,640,038 Heron 1 Feb. 8, 1972 [54] CONCRETE STRUCTURES 2,902,157 9 1959 Calver ..52/228 3,260,025 7/1966 Van Der Lely. ....52/228 [72] Inventor. Janies Heron, Samford, Queensland, Aus- 3,280,525 10/1966 Crowley u 52/224 3,300,921 l/1967 Middendorf.... ..52/224 [73] Asslgneez 'IEhexre-Load Company Inc., Garden City, FOREIGN PATENTS OR APPLICATIONS 849,458 7/ 1939 France ..52/306 [22] 1969 1,099,483 9/1955 France ..52/227 [21] Appl. No.: 859,318

Primary ExaminerHenry C. Sutherland [52] U 8 Cl 5 /22 2/2 2/ 9 Att0rneyMason, Kolehmainen, Rathbum & Wyss 52/741 [57] ABSTRACT [51] Int. Cl. ..E04b 1/06, E04b 7/20 l [58] Field of Search ..52/224, 227, 228, 229, 230, 3 a structure comiqnsmg a Precast concrete Sections, the

52/306, 248; 138/176, 155, 100 tions are arranged n generall edgew1se relationship and the edge portions of ad acent sections are spaced apart and have [56] References Cited relatively flexible or resilient material (such as biturninous or elastomenc matenal) applied thereto; a mass of setting com- UNITED STATES PATENTS position is provided between the edge portions of each two adjacent sections, to form joints between said sections, and the 885,371 4/1908 Petracch1.. ..52/248 Structure is stressed by means of stressing rods or cables so as 2,110,885 3/1938 ..52/306 to maintain Said joints in permanent compression and to 2 312 233 2; 13:? gglg s render them substantially fluidtight. 2,483,175 9/1949 Billner ..52/224 9 Claims, 7 Drawing Figures I 3,640,038 PATENIEUFEII II'IIII SHEET 2 II 3 Q H H II "I"; 1 TI [L I n I I I I I T" I I II II I I I I I "L H II I I I I I I I I II I I II II I I I I II I I I I I I I I I I I I :I :L {I :I I I I I I I: II I I I -v I 1 I'" I. I I I II I II I I I I I I I Il II II II I II I II I I {I III LIN II II II II III II II |I III II III I II II I 'I I I I I I I I I III I I II I I II III II II III III I II I II I I I I I II I I I I I I I, I I I I II I II I I II I I II II a I M I 7 I n IIII I I I [I I- IW I I; I II I II II I II I1 I I 1 1 II I I I I I I I I I I I II I I I I I I I I I I I I I I I I I II I I I I I I I I I l I I I II I I I III II II II II |I I I I I wJI I I I I I II I I I I I II I I I I I I I I I I I I I I I I I I I I I I I I I I I; I I I II II I II II II II II I II I I I'I I I I I I I I. II I I III II I I II I, ii ;I l I II II I I. ;I ,I l II I I I I I I I .I 'I I I I I I I I I A I II H II II I II II II II |I I| I |I II I I I I I I II I| II II II I I I I I I I I II I I I II II II II II II I: II II II II II II I| II I I I II II I II I I I I I I| I I' I l I I I I I I I I I II I I I| I II I I| I] II II I I I I I I I I I I I I I I II II I I I I I I I I II LR II II I I I I All II I] I I II I II I l l I ll I- I II I I I I I =.I I IIIIIIIII I I I (a I I I I I I II I I II II I RI II II I I I I I I I I l I I I II I l CONCRETE STRUCTURES This invention relates to concrete structures and particularly to such structures as are assembled from precast concrete sections with the joints between the sections in permanent compression.

One object of the invention is to provide an improved method of assembling precast concrete sections to form such a structure.

It is a more specific object of the invention to provide a method which will enable precast concrete sections to be assembled together in a convenient and effective manner to form a structure, the wall of which is substantially fluidtight.

According to the invention there is provided a method of assembling precast concrete sections to form a structure, wherein the precast sections are arranged in generally edgewise spaced relationship, with the edge portions of adjacent sections defining a gap between them, relatively flexible material being applied to the edge portions of the sections and the gap between each two adjacent sections being filled with a setting composition such as wet concrete, the joints between the sections thereafter being permanently stressed in compression.

The flexible material may be a bituminous composition, which may conveniently be applied to the edge portions of the sections in the form of a paint. Alternatively an elastomeric material such as rubber can be applied to the edge portions; such a material can be applied in the form of a sheet. The flexible material may be applied to the edge portions of the sections either before they are brought together and erected in the positions which they will occupy in the finished structure, or after they have been so erected.

When precast sections are assembled together by the method of the invention, a highly efficient fluidtight joint will be formedbetween them, despite the irregularities and inaccuracies which exist in the edges of precast concrete sections when these are made to normal manufacturing tolerances. The degree of fluidtightness achieved if the method of the invention is employed will be much better than that which can be achieved if one assembles precast concrete sections together, with their edges butted against one another and with the intervention only of a bituminous or elastomeric sealing material but without the use of wet concrete or other setting composition. The degree of fluidtightness achieved by the method of the invention will also be much better than that which can be achieved if one attempts to seal the joints between precast concrete sections solely by the use of concrete, without the use in addition of a flexible material as referred to above.-

The invention is particularly applicable to the erection of structures for the storage of liquids and gases, in which case the method of the invention will result in the formation of joints which are highly effective in preventing the egress of the liquid or gas being stored. However the invention is also applicable to the assembly of underground structures, such as underground tanks for the storage of natural gas in gaseous or liquid form, in which case the joints produced will be highly effective in preventing the ingress of ground water.

The invention will now be further described, by way of example only, by reference to one particular method in accordance therewith, for the erection of a water storage tank, reference being made to the accompanying drawings in which:

FIG. 1 is a perspective view of the tank erected by the method of the invention;

FIG. 2 is a vertical sectional view on the line A-B in FIGS. 1 and 4, broken as indicated by dot-and-dash lines, so as to enable parts of the structure to be shown on a scale larger than that of FIG. 1;

FIG. 3 is a developed view, seen from the exterior, of a part of the wall of the tank, broken away at the positions indicated by the lines A and C in FIGS. land 4;

FIG. 4 is a horizontal sectional view taken on the line D-D in FIG. 3;

FIG. 5 is a sectional view on the line E-E in FIG. I, drawn to a larger scale so as to show details of a joint in the structure;

FIG. 6 is a sectional view on the line FF in FIG. I, and

FIG. 7 is a sectional view corresponding to FIG. 5 but showing a modified form of joint.

Referring to the drawings, and particularly to FIGS. 1 and 4, there is shown a tank 1 of generally cylindrical form. The cylindrical wall thereof is assembled from precast concrete segments or sections of generally arcuate cross section. The cylindrical wall of the tank is assembled from 16 such segments having bores extending therein for the passage of stressing cables or rods, as will be described more fully hereinafter. The 16 segments referred to include two segments 11 and 12 of similar construction which are located opposite one another in the finished tank, and two further oppositely located segments 13 and 14 which also are similar to one another, but are somewhat different from the segments 11 and 12. The remaining 12 segments (such as the segment 15 for example) are similar to one another.

During the assembly of the tank, a concrete base 16 islaid down and the segments are erected on the base in edgewise relationship, so as to correspond to the desired configuration of the cylindrical wall of the tank, but with the edges of adjacent segments spaced apart to define gaps between them. Thus, for'instance a gap is left between the adjacent vertical edges 17 and 18 of the segments 11 and 15 (see FIGS. 4 and 5). Bituminous paint is applied to the vertical edges of the segments, as shown at 19 in FIG. 5. This may be done either after the segments are erected in the positions which they will occupy in the finished tank or before they are so erected, whichever proves to be more convenient in practice.

Next stressing cables are passed through the bores in the segments, circumferentially of the wall of the tank. For this purpose, each of the 12 segments such as 15 has bores such as 21 (FIGS. 4 andS) extending in the thickness thereof from one vertical edge 18 to the other vertical edge 22. A plurality of such bores is provided in each segment 15, distributed over the height thereof (see FIG. 3). Each of the four segments 11, 12, 13 and 14, on the other hand, is constructed so that only alternate stressing cables will extend continuously therethrough. At positions intermediate between these continuous bores, provision is made for crossing over the end portions of two stressing cables and bringing them out to the exterior, as clearly shown in FIG. 4, for subsequent stressing. Thus it will be noted that each stressing cable is of a length slightly greater than one-half the circumference of the tank and extends through the thickness of the tank, from one of the segments ll, l2, 13 or 14 as far as the diametrically opposite segment, bridging the gaps between adjacent segments. The

cables are a loose fit in the bores in the segments.

The parts of the stressing cables which are exposed in the gaps between adjacent wall segments are enclosed in suitable sheathing. This sheathing consists of hemicylinders 51, 52 (FIG. 5) of metal or plastics material which are fitted around the cables 24 where they extend across the gaps and are held together, by means of adhesive tape for example. The sheathing formed in this way is a loose fit around the cables, so that the void formed by the sheathing around each cable 24 in each gap constitutes a substantially fluidtight continuation of the voids around the cable, where this extends in the bores on either side of the gap. Thus each cable 24 extends through the segments and across the gaps between the segments, in a substantially continuous void space, the ends of the cable being brought out to the exterior in the manner already mentioned.

Next the gaps between the adjacent segments are filled with wet concrete, form work being used if necessary to support the concrete until it has set. Thus, as can be clearly seen in FIG. 5, the join between the adjacent segments 11 and 15 is formed by a mass of concrete 23 between the two layers of flexible material 19 provided by the bituminous paint.

After the concrete 23 has set, the stressing cables 24 are placed under tension and the ends of the cables are secured in position by the use of wedges such as 25 (FIG. 3), thus placing the joints between the segments in permanent compression. Grouting mixture is pumped in where the cables are brought out to the exterior, so as to fill the voids in which the cables extend.

It will be noted that the bores in the segments are spaced more closely near the bottoms of the segments, so as to allow for the greater outward thrust near the bottom of the cylindrical wall of the structure.

Preferably, when the segments are erected on the concrete base 16, rubber strip 26 (FIG. 2) is interposed, so as to provide a flexible mounting for the segments. Subsequently, when the cylindrical Wall has been completed, the join between the segments and the base is sealed, at the interior of the tank, by means of a sealing compound as indicated at 27 in FIG. 2. A thiosulphide sealing compound is suitable for this purpose.

Once the cylindrical wall has been completed, the roof of the tank can then be assembled thereon. The roof comprises 16 substantially identical segments such as 31, 32 in the form of truncated radial sectors, the truncated ends of which together define a polygonal opening 33 at the center of the roof. These segments form a pitched roof, being dimensioned so that they bear against one another and mutually support one another in their pitched positions. The central opening 33 is closed by a polygonal element 34 in the nature of a keystone.

As can be seen from FIG. 6, the abutting edges of the segments forming the roof are cut away so that channels 35, 36 are formed between them. These channels are filled with successive layers of plastics composition (such as a polystyrene composition) as indicated at 37, cement mortar as indicated at 38 and a sealing compound as indicated at 39. In a similar manner, referring to FIG. 2, the join, on the one hand, between each roof segment 31 and the wall segment which supports it and, on the other hand, between the roof segment 31 and the keystone. 34, may be filled with cement mortar as indicated 40, 41 and a sealing compound as indicated at 42, 43, the sealing compound being applied at the exterior of the joint. In the case of the joints between the roof segments and the cylindrical wall of the tank, it is also desirable to insert a rubber strip extending circurnferentially between the vertical abutting surfaces of the wall and the roof, where the outward thrust of the roof segments is applied to the wall segments. Such a strip is shown at 44 in FIG. 2, where the outward thrust of the roof segment 31 is applied to the wall segment 15.

After the structure has been completed, earth may be banked up around it, as indicated at 45 in FIG. 2. A pipe 46 serves for the discharge of water from the tank.

One of the roof segments may be formed with a manhole, to allow the interior of the structure to be inspected.

As an alternative to applying bituminous paint to the adjacent vertical edges of the segments forming the wall of the tank, it would be possible to apply flexible or resilient sheet material to the edges of the segments using an adhesive, as indicated in FIG. 7, where strips 119 of sheet material are applied to the edges of the segments 111 and 115 by means of adhesive 120. The sheet material may be bituminous material or an elastomeric material such as rubber and the adhesive may conveniently be that known as Bostik.

I claim:

l. A method of assembling precast concrete sections to form a vertically extending, fluidtight structure comprising the steps of positioning a pair of adjacent precast sections arranged in generally edgewise spaced relationship, with vertical, facing edge portions of said adjacent sections defining a gap between them, applying relatively flexible sealing material to said facing, vertical edge portions of said sections, filling the remaining space in between said adjacent sections with a composition which sets into a relatively rigid state to form a joint between said adjacent sections and thereafter permanently stressing said joint in compression so as to compress said composition between said flexible sealing material onsaid edge portions, thereby rendering said joint substantially fluidtight.

2. A method according to claim 1, wherein said sealing material is applied to said edge portions in liquid form and is dried, thereby forming said flexible sealing material.

3. A method according to claim 1, wherein said flexible sealing material is applied to said edge portions by adhesively securing a layer of elastomeric material to said sections.

4. A me od according to clarm 1, wherein said flexible sealing material is applied to said edge portions before said sections are brought together in edgewise spaced relationship.

5. A method according to claim I, wherein said flexible sealing material is applied to said edge portions after said sections have been arranged in edgewise spaced relationship.

6. A method according to claim 1, including the step of passing stressing elements through preformed bores in said sections, so as to bridge said gaps between adjacent sections, before said gaps are filled with said setting composition, said stressing elements being used for placing said joints in permanent compression.

7. A fluidtight structure comprising a. a number of precast concrete sections arranged in generally edgewise relationship, each section having a plane, end edge face,

b. said end edge face being arranged in spaced-apart relationship with the end edge face of an adjacent section and each end edge face having its entire surface coated with a layer of relatively flexible material,

c. a mass of setting composition in the space between said layer on the end edge faces of two adjacent sections which forms a joint between said sections but does not come into direct contact with the precast sections and d. said structure being stressed to maintain said joint in per- 7 manent compression and render said joints fluidtight.

8. A fluidtight structure as claimed in claim 7, wherein said sections are formed with bores extending between opposite edge portions thereof, stressing elements being arranged in said bores and passing between said sections so as to bridge said joints and to maintain them in compression.

9. A fluidtight structure as claimed in claim 8, wherein said sections are arranged to form a generally cylindrical wall and said stressing elements extend in a circumferential direction around said wall. 

1. A method of assembling precast concrete sections to form a vertically extending, fluidtight structure comprising the steps of positioning a pair of adjacent precast sections arranged in generally edgewise spaced relationship, with vertical, facing edge portions of said adjacent sections defining a gap between them, applying relatively flexible sealing material to said facing, vertical edge portions of said sections, filling the remaining space in between said adjacent sections with a composition which sets into a relatively rigid state to form a joint between said adjacent sections and thereafter permanently stressing said joint in compression so as to compress said composition between said flexible sealing material on said edge portions, thereby rendering said joint substantially fluidtight.
 2. A method according to claim 1, wherein said sealing material is applied to said edge portions in liquid form and is dried, thereby forming said flexible sealing material.
 3. A method according to claim 1, wherein said flexible sealing material is applied to said edge portions by adhesively securing a layer of elastomeric material to said sections.
 4. A method according to claim 1, wherein said flexible sealing material is applied to said edge portions before said sections are brought together in edgewise spaced relationship.
 5. A method according to claim 1, wherein said flexible sealing material is applied to said edge portions after said sections have been arranged in edgewise spaced relationship.
 6. A method according to claim 1, including the step of passing stressing elements through preformed bores in said sections, so as to bridge said gaps between adjacent sections, before said gaps are filled with said setting composition, said stressing elements being used for placing said joints in permanent compression.
 7. A fluidtight structure comprising a. a number of precast concrete sections arranged in generally edgewise relationship, each section having a plane, end edge face, b. said end edge face being arranged in spaced-apart relationship with the end edge face of an adjacent section and each end edge face having its entire surface coated with a layer of relatively flexible material, c. a mass of setting composition in the space between said layer on the end edge faces of two adjacent sections which forms a joint between said sections but does not come into direct contact with the precast sections and d. said structure being stressed to maintain said joint in permanent compression and render said joints fluidtight.
 8. A fluidtight structure as claimed in claim 7, wherein said sections are formed with bores extending between opposite edge portions thereof, stressing elements being arranged in said bores and passing between said sections so as to bridge said joinTs and to maintain them in compression.
 9. A fluidtight structure as claimed in claim 8, wherein said sections are arranged to form a generally cylindrical wall and said stressing elements extend in a circumferential direction around said wall. 